The normal expectation is that if a later version of the module uses new features of perl, it will set the required version of perl accordingly. If it uses new features in a module, it will set the required version of that module appropriately.

Core modules generally tend to get more testing and more review than non-core modules, so in the general case I would expect upgrading dual-life core modules to be less dangerous than upgrading non-core modules (assuming you install them only if the tests pass). That said, neither review systems nor code are ever perfect, there will always be some risk of breakage - it's always good to have a plan for how to back out a change.